build(protractor): IButton unkown in typings

Author: SteveVanOpstal

package.json

@@ -133,7 +133,7 @@
     "mocha": "^3.0.0",
     "phantomjs-polyfill": "^0.0.2",
     "phantomjs-prebuilt": "^2.1.7",
-    "protractor": "^4.0.8",
+    "protractor": "4.0.6",
     "raw-loader": "^0.5.1",
     "rimraf": "^2.5.2",
     "s3": "^4.4.0",